1. Field of the Invention
This invention pertains to the field of mine safety and more specifically the provision of safe havens in underground mines to provide safe refuge for miners unable to escape their work area immediately after a disaster due to toxic gases or a blocked escapeway.
2. General Background of the Invention
In many mining disasters in underground mines, many miners survive the initial disaster only to lose their lives due to an inability to escape from or isolates themselves from poisonous gases that build up in the mine in the wake of the disaster. For example, in 2006, there were three major mining disasters involving fire or explosion. In these events, 19 miners lost their lives despite surviving the initial disaster.
In the wake of these 2006 disasters, the MINER Act (Mine Improvement and New Emergency Response Act of 2006) was enacted. As part of the mandate of the MINER Act, NIOSH was charged with researching refuge alternatives to determine what alternatives would provide the best protection for miners following a disaster. The primary function of a refuge alternative is to provide a safe haven for miners unable to escape their work area immediately after a disaster due to toxic gases or a blocked escapeway. To be effective, a refuge alternative must, at a minimum, survive the initial disaster. In addition, it would be beneficial if the refuge alternative would protect the miners from any secondary explosions. This research considered both built-in-place and portable refuge chambers (i.e. safe havens).
The research concluded that built-in-place alternatives were highly preferable. Such alternatives provide a superior environment to miners using them for refuge, which can beneficial to the health of the miners following a disaster. Such built-in-place alternatives also provide the ability to deliver an unlimited supply of breathable air through a borehole or a protected compressed air line, examples of the latter being the Hubble® Breathable Air Units (Models HBA 75, HBA 100, and HBA 250) that have been approved by MSHA for such use.
In an April 2015 NIOSH report1 focused on facilitating the use of built-in-place safe havens, the authors noted that there were approximately 30 built-in-place safe havens in use in underground coal mines in the U.S.; none of which were capable of being relocated as the working face is advanced. The ability to relocate the safe haven is, however, highly desirable to keep the safe haven within the preferred distance from the working face of the mine. But the benefits of a built-in-place safe haven are so great, a 2007 report to Congress in the wake of the MINER Act advised that, if a built-in-place safe haven is used, permitting extended distance from the working face should be considered despite the obvious additional risks this would pose to miners, especially injured miners, in getting to the safe haven before the air available through the miner's self-contained self-rescuer is exhausted. 1 NIOSH [2015]. Facilitating the use of built-in-place refuge alternatives in mines. By Trackemas J D, Thimons E D, Bauer E R, Sapko M J, Zipf R K, Schall J, Rubinstein E, Finfinger G L, Patts L D, LaBranche N. Pittsburgh, Pa.: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2015-114, RI 9698.
Thus, it is clear that there is need for an apparatus that can be used to create the equivalent of a built-in-place safe haven in an underground mine that is also capable of being relocated as the working face of the mine advance. The present invention addresses this need. Unlike the known examples discussed above, the present invention is an adjustable height wall that can be assembled outside the mine and transported to the desired safe haven location at a lower cost than constructing a permanent wall in place. Once transported to the desired location in the mine, the wall of the present invention can be installed to create the equivalent of a built-in-place safe haven. Moreover, as the working face advances, the wall of the present invention can be relocated within the underground mine to keep the safe haven within the preferred distance from the working face. Thus, the present invention provides the equivalent of a built-in-place safe haven with all of the attendant benefits at a lower cost without the need to consider allowing it to be located further from the working face.